Slate brick



Reiasu'ed My 6, 1924. v Re. 15,829 UNITED STATES PATENT OFFICE.

EMIL PL ENGELBRECHT, OP PITTSBURGH, PENNSYLVANIA, ASSIGNOR, BY DIRECT AND HESNE ASSIGNHENTS, TO TO'UPET-TAYLOR ENGINEERING COMPANY, A CORPORA- TION OF PENNSYLVANIA. I

SLATE muck.

Serial No. 412,573, an m 25, 1921. 1924. Serial in. 886,463.

' No Drawing. Original 1%. 1,462,596, dated an 24, 1923, Application'tor reissue filed January 13,

neighborhood of from three to five per cent; t e greater the percenta e of binder, the stronger the brick." For t fireproof brick, about five or other binder is used.

This round slate and lime is then mixed thoroug i'ly and is passed'into a grinding mill, and the mixture is thoroughly ground together with a suitable amount of water. Just enough water is used to properly slack the lime, or to render the binder and the entire mixture plastic, without any surplus water, the mixture, therefore, remaining substantially dry. The exact amount of water used depends upon the condition of the mixture, the slate sometimes containing .more or less moisture. My invention consists in part in rinding this mixture properly,'the objecting to much more thoroughly mix the substances by grinding in"con unction with the proper amount of water, so as to cement together with the binder as great a surface area of the grains of slate as is possible, thereby making the brick stronger and less liable to be disintegrated by intense heat or cold. e amount of grinding, however, depends upon the quality and natureof'the bricks desired, and the exact amount being more or less immaterial. The grinding, however, is carried on while the mixture is still moist and the lime is slacking, and it is continued until a coherent mass is formed which will not crumble apart when pressed together. A suitable test is to take a mass in the hands and pack it together, a'nd then press the thumb into the mass. If th me ly breaks apart, in one or two pieces, but does not crumble to pieces, the grinding process has reached the final stage. If the mass crumbles, the grinding is not sufiicient, or if it isso coherent or plastic as not-to break apart at all, the amount of moisture is too great, or the grinding is too much.

' e ground material is then passed into the brick-press. Any ordinary brick-press may be used. The material is then put un er a pressure in the neighborhood of two and one-half tons per square inch; the amount of pressure depending upon the density of the brick desired. The bricks "are then passed in a heating chamber, which usually consists of a long tubular casing, and steam is passed into 7 '0 all whom it may concern: I Be it known that I, EMILP. ENGELBRECHT, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain newand useful Improvements in Slate Bricks, of which the following is a specification.

This invention relates to' bricks, hollow 10 blocks, tiles, and the like, and consists in a I novel process for manufacturing suchbricks, hollow blocks, tiles, and other articles which are required to be of the general nature of bricks. The invention consists also in the novel product produced by the carrying out of my process. For convenience, I shall refer herein to the products merely as bricks, but it is to be understood that 'ingeneral the' statements refer to hollow blocks, tiles, and other similar articles as n well. f e One of the purposes of my rocess is to produce bricks which will wit stand very intense heat continuousl for a long time, and hence are ordinari y called fireproof brick. Another purpose is to roduce bricks of the nature that will be fufly as effective as ordinary fireproof bricks, as to dura bility,looks, and the like, but that will be less expensive to manufacture.

. e process which I .have invented for manufacturing these bricks consists in using as-the princi al material therefor, what is ordinarily ca led red dog. This is a sub- 5 stance which is formed from coal-mine slate,- which is a grayish slaty substance which is formed in the shape of veins in coal beds, and is separated fromthe coal as it is mined, and ordinarily thrown out as waste. This slate is thrown-out by the miners into enormous piles of thousands of tons, and spontaneous combustion arises therein, and the combustible substances contained in the slate, such as sulphur, and the like, are burned out. This burned substance is'. called red dog.

My mvention cons sts in taking this burned slate and crushingit and then grinding it into fine particles, somewhat smaller than ordinary grains of sand. I prefer to grind it up-until the larger particles are no more than about one-sixteenth ofan inch thick. I then add a small pro ortion of unslacked lime, or other similar inder, in the" per cent of ime the casing, and the e best qualit of e mass then proof bricks are unita binding element, addin suflicie'nt' water to render the mixture p astic grinding the mixture together until it is't oroughly com-" mingled andifoms a coherentjmass, subjecting the mixture to ressure and shapinignunitary portions to esired form, and ally subjecting the formed units to heat.

5. The rocess of manufacturing bricks and the ike consistin' in mixing with burned and granulated coa -mine slate, commonly known as red dog, a proportionately small amount of suitable bin ing bricks are heated thereby for about nine hours, the steam being kept at a pressure of about 125 pounds. At the end of this heating, the bricks are completed- If the rocess is. roperly carried out, fireined which will stand a continuous temperature of 2285 degrees The bricks can be used for building walls, foundations, and the like, or wherever they will be ex d to intense temperature; and tiles and other articles for mosaic work or the like may be made in a similar manner. The surfaces of the articles may be enameled or colored in any the mixture plastic, grinding the mixture ordinary manner, and wherever unusual together until it is thorough y commingled and forms a coherent mass, subjecting the strength is desired, as in foundations, or wherever resistance. to great crushing mixture to ressure and sha mg unitary rtions to esired form, an finally snbstrains is'necessary, cement may be substituted for lime as a binder. ectin the formed units to heat;

. I claim as my invention: 6. article of manufacture composed of 1. The recess of manufacturing bricks a mixture of burned and granulated-coal and the ike consisting in mixing with mine slate, and a proportionately small burned and nulated coal-mine slate a amount of unslacked lime, with suflicient proportionate y small amount of unslacked' moisture to substantially slack the lime, the lime, in adding an amount of water suffimixture being suitably ground together and cient to substantially slack the lime used, pressed into shape, and heated for substanin grinding the mixture together until it tially nine hours at a temperature of about forms a coherent mass, in pressing the three hundred and fifty. degrees Fahrenground-.mixture into proper shape under. heit. apressure of from'two to two and one- 7. An article of manufacture composed of half tons per square inch, and in heata mixture of burned and granulated coaling' the pressed articles for about nine Fahrenheit.

element, adding suflicient water to render mine slate and a proportionately small hours in a bath of steam under a pressure amount of binding agent, sufiicient moisture of about one hundred and twenty-five torender such binding agent efiective, the pounds. entire mixture being groun and thoroughly 2. The process of manufacturin bricks mixe ndpr s in h p nd th n sub" consisting in adding to burned an granujected to heat. lated coal-mine slate from three to five 8. An article of manufacture composed of per cent of unslacked lime with suficient a mixture of burnedand granulated coalwater to substantially slack the lime, in mine slate and a p' portionatcly small amount of cementitious binding agent, sufigrinding the inixtureyntil it forms a coherent mass, in pressmg the bricks under cient moisture torender such binding agent-' a pressure 0 about two and a half tons per effective, "the entire mixture being un squareineh', and in heating the bricks for and thoroughly mixed and presse into shape.

substantially nine hours at atemperature of 9 A about three hundred d fifty degrees Faharticle .-'of manufacture of I a mixture. of. burned-and granulated coal red d' renheit.

3. The races of manufaeturing bricks mine slate hommon ly known as o I and the ike consisting in mixing' with and a'proportionately small amount of bin burned and 1 nulatedcoal-mine slate a ing agent, suflicient moisture to render such. proportionate ,y small amount of suitable binding agent efl'ective, the entire mixture in element, addin suflicient water to being round and thoroughly mixed and render 'th'e-Jmixture p astic, grinding t" f into shape, and t on subjected'to mixture together until it is thoroughlyoom-' I t. Y 1 mingled and forms a coherent mass, subject- '10. An article of 'manufacture com osed ing the mixture to presure. and shaping of a mixtureofburned and granulated'eoalportions to desired form. mine slate commonly known as dog" 4. e of manufacturing bricks and a proportionately small amount of and the ike consisting in with binding agent. v burned and granulated -mineslate s In testimon whereof I afix masignature.

y of suitable c MIL P. ENGELB ECHT.

proportional small amount 

